LOS ANGELES (AP) — About 20,000 students in California who need to learn English aren’t getting adequate language instruction, according to a lawsuit against the state and education workers filed Wednesday by the American Civil Liberties Union.

Under state and federal law, schools are required to teach non-English speakers the language, but by its own records, the state isn’t offering English instruction to nearly 20,000 students. The suit alleges that lack of instruction has meant some children had to be held back a grade or live with low proficiency scores because of a language barrier.

The ACLU brought the issue to the attention of the state with a letter in January, and officials say they’re working to ensure compliance at the local level.

Attorney Mark Rosenbaum said in Wednesday’s filing that English learners fall behind without proper language lessons, even as school districts collect federal funds for providing such education.

“These kids are not getting the differentiated learning they’re supposed to be getting,” Rosenbaum said.

Chief Deputy Superintendent of Public Instruction Richard Zeiger said in a statement that the state is determined to provide English learners appropriate instruction and encouraged parents to bring problems to the state’s attention.

“The Department will continue to work with local agencies to ensure compliance with districts’ obligations to provide services to English learners,” Zeiger said.

Zeiger also noted that a recent appellate court decision found that the department was meeting its legal obligations related to on-site monitoring of English learners.

The ACLU’s lawsuit describes the educational struggles of three families with Spanish-speaking children attending Compton Unified School District and a San Diego 18-year-old in the Grossmont Union High School District.

In each case, schools identified the students as English learners but were later taken out of English language classes and saw their grades drop dramatically in courses where they struggled to understand instruction, the suit alleged.

One mother had both of her children, an 8-year-old and a 10-year-old, held back a year immediately after they stopped being provided language instruction, the suit alleged.

Rosenbaum said parents often didn’t know their children had been taken out of language classes, and in one case, a mother was told to bring her own translator to school meetings to get an explanation.

In response to the January letter, school officials acknowledged the problem while adding more than 98 percent of the state’s 1.4 million English learners are receiving services.

The suit seeks a court order for schools to provide courses to English learners who need them, attorney’s fees for filing the suit and unspecified further equitable relief the court finds appropriate.